Grate structure for burning solid fuel



Feb. 27, 1934. G. DALEN GRATE STRUCTURE FOR BURNING SOLID FUEL Filed April 30, 1932 INVENTOR 4/5 ATTORNEY Patented Feb. 27, 1934 UNITED STATES PATENT OFFICE 7 1,948,699 GRATE STRUCTURE FoR BURNING s'otm FUEL 1 Claim. (01. 126-182) The present invention relates to grate structure forburning solid fuel. More particularly, the invention relates to grate structure for burningsolid fuelcontinuously and at relatively low rates of combustion in a fuel burning device in which a considerable quantity of solid fuel is stored in a magazine within the device and fed by gravity to the grate. Still more particularly, the invention relates to grates for burning solid fuel in domestic cooking stoves of the fuel storing and heat accumulating type such as is disclosed in U. S. Patent No. 1,559,162 granted to me October 27, 1925. t a For purposes of illustrating the invention, 1 i have chosen by way of example a domestic cooking stove of the type disclosed in the above mentioned patent, but it will be appreciated that in its broader aspects the invention is not limited to use in the particular type of device herein disclosed but may beused in other solid fuel burning devices.

Amongst the several objects of the invention are to provide a rotary grate adapted to support 5 a supply of solid fuel retained in a magazine situated above the grate; to provide a grate .of non-clogging type which will permit thepassage throughor removal from above the grate of noncombustible impurities in the fuel, such as slate, rockor the like, without necessitating removal of the grate or other disturbance of the fire, whereby to permit continuous and uninterrupted combustion to take place; to provide grate structure of the character described which is readily removable for purposes of replacement or repair to provide a grate carrier of novel form for supportingthe grate; to provide a grate carrier which is readily removable as a unit with the grate from the device of which it forms a part and to provide grate structure of the character described having further and more detailed advantages as will hereinafter more fully appear. Inthe accompanying drawingforming a part of this specification, there is illustrated a preferred formof the invention as embodied in a domestic cooking stove of the magazine, heat accumulating type above referred to.

Fig. 1 is a front elevation partly in section of a stove embodying the invention;

Fig. 2 is a plan view on a larger scale of grate structure illustrated in Fig. 1;

Fig. 3 is a section taken on the lines 33 of Figs. 1 and:2; i 5

Fig. 4 is a sideelevation on a further enlarged scale taken on the line 4-4 of Fig. 2;

I the Fig, 5 is a central vertical section of the grate with an operating tool applied thereto, and,

Fig.6 is a view looking toward Figure 5 from below. i

Referring now more particularly to Fig. 1, the 80 stove illustrated comprises a casing 10 of metal or othersuitable material within which is supported from any suitable member, such as the member 11, a combustion housing indicated at 12. This housing is of generally annular form and at the bottom thereof is advantageously lined with suitable refractory material 13. The upper end of the casing 12supports a heavy metal block l lcomprising a freely depending annular skirt portion 15 and a thick annular head 16;the upper surface 17 of which provides a cooking plate surface. Theopening in the head 16 is closed by the removable :cap or cover plate 18.

Supported by any suitable member such as indicated at 19 is the casing 20, the upper portion Zloi which surrounds the lower portion of the housing 1? As will be observed from the drawing, a sliding joint is provided between the housing 12 and the'casing 20 to permitexpansion and m contraction of the former without hindrance. This sliding joint is made substantially air-tight by meansof any suitable form of packing such as the rope packing indicated at 22. The lower portion 23 of thecasing 20 provides an ash pit 24 having an opening indicated 25 (Figs. 2 and 3) communicating with the front of the stove. This opening is closed by any suitable form of ash pit door 26. l

, As will be noted from Fig. 1, the skirt portion 15 of the block 1'4 is spaced from the housing 12 and refractory material 13 so as to provide a fire space 2'7 and an annular space 28 communicating therewith for flow of combustion gases. The space 28 communicates with passage 29 through which the combustion gasespass to a chimney (not shown) through a suitable outlet 30 extending to the back of the stove.

In the particular form of stove illustrated, a second metal heat accumulating member 31 .is provided and the cooking plate surfaces of this member and of the member 14 are advantageously covered whenthe stove is not in use by heavily insulated removable covers 32; Heat from the combustion gases which is absorbed and accumu- I lated in thestove is utilized in ovens 33 and 34. The specific oven construction of the stove is not germane to the present invention and accordingly will not be described in detail.

V The space within the casing 10 which is not occupied by the several elements of the stove is preferably filled with any suitable form of insulating material indicated generally at so as to reduce loss of the accumulated heat by radiation to a minimum.

Turning now more particularly to the grate structure, this structure comprises a grate carrier 36 removably supported within the casing forming the ash pit and in turn having revolubly mounted thereon the grate 37.

As will be observed from Figs. 2 and 3, the grate carrier 36 is in the form of an X-shaped spider having arms 38, 39, 40 and 41 and a central supporting portion 42 in the form of an upstanding pin which is preferably of truncated conical configuration.

The grate member 37 comprises a central hub 43 and an outer rim portion 44 joined by a plurality of generally spiral grate bars 45. As will be observed from Fig. 2, these grate bars provide a series of spiral shaped interstices, the purpose of which will be explained later. Obviously, the number of bars 45 may be varied to provide interstices of the proper size for the fuel to be employed. The lower edge of rim 44 is notched or serrated as at 46 and the hub portion 43 is recessed as at 47 to provide a bearing surface for the supporting portion 42 of the gear. As appears from Figs. 3 and 5, the grate bars 45 taper from the hub toward the rim so that the enveloping surface of the top of the grate member is generally conical.

Arms 38 and 39 of the carrier are provided at their ends with projecting lugs 48 and 49 respectively, these lugs providing engaging portions adapted to slide respectively on the guide members 5G and 51 carried by the side walls of the casing 23. As appears more clearly in Fig. 3, wherein the guide member 51 is shown, each of the guide members is inclined upwardly and rearwardly of the ash pit from the opening 25 and the upper ends of these members are advantageously bent as at 52 to provide horizontal supports for the engaging portions of the grate carrier. A latch member 53 is pivotally mounted on one side wall of the casing 23, this member being adapted to engage a cooperating latch lug 54 at the end of the carrier arm 40. As will be seen from Fig. 3, the latch 53 is adapted to hold the carrier in horizontal position when the engaging portions 48 and 49 are resting on the supporting surfaces at the upper ends of the guide members. In order to prevent tilting of the grate when it is in operative position, a lug 55 is provided which projects inwardly of the casing 23 so as to engage the end 56 of the carrier arm 41 in case the grate tends to tilt from its operative position.

The manner in which the above described structure is operated is as follows, assuming the grate to be in operative position. Solid fuel is supplied through the opening at the top of the member 14 to the magazine space provided within the skirt portion 15 of this member. The fuel stored in this magazine rests upon the grate member 37. Air for combustion purposes is admitted below the grate in any known desired manner. An adjustable air opening may be provided in the ash pit door 26 or a suitable separate opening from the atmosphere may be employed. Regulation of the rate of combustion may be effected by controlling the air inlet through thermostatic means in the manner indicated in my previously granted patent hereinbefore mentioned, or by other equivalent means.

Assuming that combustion has been started, the combustion gases from the burning fuel on the grate 37 pass laterally through the space provided between the refractory material 13 and the skirt portion 15 of the element 14 into the combustion gas passage 23 and from this passage to the chimney.

In order to maintain a clean fire, the ash should be removed periodically from the grate and this is done by turning the grate. Turning of the grate may be readily eifeoted manually by inserting through the ash pit opening 25 a hooked tool 57, the inner end of which is adapted to be hooked around the supporting pin 42 on the carrier to provide a fulcrum. Turning movement of the grate, when the tool is in operative position is effected by seating the arm of the tool in successive notches 46 in the rim of the grate.

As will be observed from the drawing, the notches 46 are arranged so that turning movement of the grate is effected in clockwise direction as indicated by the arrow in Fig. 2. This movement will tend to carry material which is too large to pass between the grate bars to the outer edge of the grate and this tendency of material to move to the outer edge of the grate, upon rotation thereof, is enhanced by the generally conical upper surface of the grate and by the screwing action of the bars 45. Due to this construction, pieces of solid foreign matter which might otherwise accumulate on the grate to such an extent as to interfere with combustion, may be removed from the grate by the normal periodic movement of the grate for the purpose of ash removal. As will be readily apparent from Fig. 2, suflicient space is provided at the front and back of the ash pit to permit relatively large foreign objects to fall from the edge of the grate into the ash pit.

If for any reason it is necessary or desirable to remove the grate from the stove, this is readily accomplished in the following manner. The hooked tool 57 is inserted under the carrier, as indicated in broken lines in Fig. 3, the portion 58 (see Figs. 3 and 6) seating in a groove 59 (see Fig. l) in the bottom of the carrier 36. With the tool in this position so that the grate and carrier may be held manually from falling, the latch 53 is pulled out of engagement with the part 54 by any suitable means such as a tool 59 adapted to removably engage the latch member 53. With the latch 53 released, the carrier and the grate, as a unit, may be tilted by lowering the tool 57 so as to bring the part 56 (Fig. 4) below the level of the lug 55. After this has been done, the unit comprising the grate and the carrier may be readily withdrawn from the ash pit. In order to insert this unit into the ash pit, it will be evident that with the aid of the hooked tool 57, the carrier can be pushed into position from the front of the ash pit, with the guides 50 and 51 serving to elevate the rearward or inner portion of the carrier to operative position, after which the grate maybe lifted by means of the tool into its horizontal operative position, in which it is held by the latch 53.

While, in accordance with the patent statutes, I have illustrated a preferred embodiment of the invention, it will be understood that many changes and variations in the details of construction may be made without departing from the scope of the invention as defined in the appended claim.

What I claim is:

In apparatus of the character described, means providing wall structure defining an ash pit having a lateral opening, means providing guides on opposite walls of said structure, said guides being inclined upwardly and rearwardly of the ash pit from said opening, a grate carrier having a central grate supporting portion and portions adapted to engage said guides to permit the carrier to be inserted in and removed from said ash pit through said lateral opening, the engaging portions of the carrier being supported at the inner upper ends of said guides when the carrier is in operative position, means in the ash pit for releasably engaging other portions of said carrier to hold the same in operative position, and a grate rotatably supported by said central grate supporting portion, said grate comprising a central hub, an outer rim and a plurality of spiral grate bars connecting said hub and said rim, the upper faces of said grate bars sloping progressively from the hub to the rim to provide a grate the enveloping upper surface of which is generally conical, said hub'comprising surfaces adapted to engage said central grate supporting portion of the carrier, and the lower face of said rim having notches providing for turning movement of the grate only in the direction tending to cause movement of material carried on the grate toward said rim by the aid of a tool inserted through said lateral opening and engaging one of said notches.

GUSTAF DALEN. 

